The
following is an example of the query process of a client
computer making a request to a DNS server to resolve the
address web address of
www.zandri.net.

First, the
client computer generates a request for the IP address of
www.zandri.net by
sending a recursive query to the DNS server that it is
configured to use in its network configuration. (We'll call
this server LOCALCFG.)

The second
step is for the LOCALCFG DNS server that has received a
recursive query to look for the name in its local database. If it does
find that answer locally, it is returned. If it is unable to
locate an entry for
www.zandri.net in its own database, it sends an
iterative query to a DNS server that is authoritative for
the root of the local domain. (We'll call this server
LOCALROOT.)

If the
LOCALROOT DNS server, which is authoritative for the root
domain, has the answer in its local database, it sends a
response to LOCALCFG. If the LOCALROOT DNS server is unable
to locate an entry for
www.zandri.net in its database, it sends a reply to the
querying DNS server (LOCALCFG) with the IP addresses of DNS
servers that are authoritative for the .net domain. (If it
were .com you would be sent the IP addresses of DNS servers
that are authoritative for the COM domain. If it were .org
you would be sent the IP addresses of DNS servers that are
authoritative for the ORG domain, and so on.) We'll call this
server DNSNET.

The DNS
server that received the client recursive query (LOCALCFG)
sends an iterative query to a server that is authoritative
for the .net domain (DNSNET).

If the DNS
server that is authoritative for the .net domain (DNSNET)
has an entry for
www.zandri.net in its local cache, it will return it to
LOCALCFG. If DNSNET is unable to locate an entry for
www.zandri.net in its
database, it will send a reply to the querying DNS server (LOCALCFG)
with the IP addresses of DNS servers that are authoritative
for the zandri.net domain. (We'll call this server ZANDRIDNS.)

The DNS
server that received the client recursive query (LOCALCFG)
sends an iterative query to a server that is authoritative
for the zandri.net domain (ZANDRIDNS).

The DNS server that is authoritative for the zandri.net domain (ZANDRIDNS)
locates an entry for
www.zandri.net in its database and sends a reply to the
querying DNS server (LOCALCFG) with the IP address of
www.zandri.net.

Finally, the DNS
server (LOCALCFG) that received the recursive query sends a
reply to the client computer with the IP address of
www.zandri.net.

Well, that wraps up this section
of "Learn Windows XP Professional in 15 Minutes a Week." I hope
you found it informative and will return for the next
installment.

As always, if you have any questions, comments or even constructive criticism, please feel free to drop me a
note. I want to write solid technical
articles that appeal to a large range of readers and skill
levels, and I can only be sure of that through your feedback.